10,000 kWh battery performance

[SnBGC]

It occurred to me that 33,000 miles is a bit of a milestone in respect to battery discharge/charge cycles. At 3.3 mi/kWh then I have discharged and recharged about 10,000 kWh through the HVB pack. I am kinda curious how much degradation has occurred but I am not able to observe any. It's possible that some of the upper buffer is consumed and glancing at my (somewhat incomplete) notes with data from early readings it appears that maybe around 1% of the upper buffer has been consumed?

Either way.....that still seems way below industry average for BEVs so good job to Ford for what appears to be an excellent battery management strategy. I know the GOM is not an indication of battery health so take that with a grain of salt but the scan tool date is more compelling. Looks like the battery is doing just fine to me. Anyone see anything different that I am missing?

 

[Logal727]

It occurred to me that 33,000 miles is a bit of a milestone in respect to battery discharge/charge cycles. At 3.3 mi/kWh then I have discharged and recharged about 10,000 kWh through the HVB pack. I am kinda curious how much degradation has occurred but I am not able to observe any. It's possible that some of the upper buffer is consumed and glancing at my (somewhat incomplete) notes with data from early readings it appears that maybe around 1% of the upper buffer has been consumed?

Either way.....that still seems way below industry average for BEVs so good job to Ford for what appears to be an excellent battery management strategy. I know the GOM is not an indication of battery health so take that with a grain of salt but the scan tool date is more compelling. Looks like the battery is doing just fine to me. Anyone see anything different that I am missing?

Seems pretty on par with other EV batteries, with the right BMS you can make these last a long time, so, yep they are doing it right

 

[IamIA]

Thanks for sharing.
Percentage-wise, how many of those charges were to 100%?

 

[SnBGC]

Thanks for sharing.
Percentage-wise, how many of those charges were to 100%?

About 35%-40% I think.
I have to charge to 100% displayed during the summer in order to have the ability to cool the battery while parked on plug without also charging.

I also starting charging to 100% about a month ago to see if that would eliminate the random "failed to charge overnight" or very frequent "ignore departure time" events. However both of those still occur. Much less frequent, but they still occur.

I will probably change it back to 90% until June or July when it will go back to 100% again.

 

[Jimrpa]

About 35%-40% I think.
I have to charge to 100% displayed during the summer in order to have the ability to cool the battery while parked on plug without also charging.

I also starting charging to 100% about a month ago to see if that would eliminate the random "failed to charge overnight" or very frequent "ignore departure time" events. However both of those still occur. Much less frequent, but they still occur.

I will probably change it back to 90% until June or July when it will go back to 100% again.

I don’t understand? Why do you have to charge to 100% in the summer to cool the battery? I thought the battery got warmer when charging?

 

[SnBGC]

I don’t understand? Why do you have to charge to 100% in the summer to cool the battery? I thought the battery got warmer when charging?

It does warm up while charging, which is why I don't want to charge during the day when ambient temps can be over 120F. I only want to charge during 11pm-5am during the summer since it is cooler then and my electric rates are less expensive.

Previous Ford BEVs would cool the battery when parked on plug even outside of the charge schedule. So I could park my Focus Electric at work or home and plug in but NOT charge. Then when the HVB gets hot just by sitting out in the sun, the A/C would kick on and chill the battery. Very nice feature.

For whatever reason, the new Team Edison decided to restrict that feature to only activate inside the charge schedule. Which kinda sucks because now we are creating even more heat to manage AND paying the higher electric rates!

Fortunately @macchiaz-o discovered a work around. If I open the charge schedule to include daytime hours but lower the charge limit to 50% then I can plug in and NOT charge but the car WILL cool the battery when needed.

Edit: ....and thus the need to charge to 100% to ensure that I don't fall below 50% during my day. I have several days each when where I consume more than 40% charge before arriving home.

 

[generaltso]

Fortunately @macchiaz-o discovered a work around. If I open the charge schedule to include daytime hours but lower the charge limit to 50% then I can plug in and NOT charge but the car WILL cool the battery when needed.

I was just about to ask why you wouldn't just lower the max charge to something less than 100%.

 

[SnBGC]

I was just about to ask why you wouldn't just lower the max charge to something less than 100%.

Yes. I forgot to circle back to the reason why I start my day at 100%.
I went back and edited my post. I need to start each day at 100% to ensure I don't fall below 50%. If there was a lower setting like 40% then I would be fine charging tp 90% each day.

 

[bshaw]

Sounds like you are taking all the precautions available to maximize your battery lifetime. Explains why your range degradation is minimal after 33k miles.

What's the ambient temp at which one should start plugging in for battery cooling purposes? We don't ever get much above 100 here, but should a 90s day be plugged-in to cool as well?

 

[Davedough]

I often worry about this because I've been charging to 100% since I got the car in December. The cold temps here were putting me at around 150 miles at 90% and sometimes I have to go further than that in a day. I needed all the mileage I could squeak out of it. I plan on backing it off as it gets warmer, but I do worry about degradation. Good to see that the battery management appears to be pretty good so far on yours

 

[SnBGC]

Sounds like you are taking all the precautions available to maximize your battery lifetime. Explains why your range degradation is minimal after 33k miles.

What's the ambient temp at which one should start plugging in for battery cooling purposes? We don't ever get much above 100 here, but should a 90s day be plugged-in to cool as well?

It was right at 97F for the Focus Electric but that was a much smaller HVB.
The MME HVB has more mass so it stands to reason it should be able to exist in higher temps before excessive thermal gain becomes a concern. There is a message on the screen that asks to be plugged in and it seems like it activates around 109F or so. It isn't a consistent threshold like the FFE though. That car would give the message at 97F every single time. The MME varies a bit so it must take the current battery temp as well as the ambient to calculate if the user should plug in. (just guessing though...)

If you have the 4P HVB then you are probably fine with temps up to 100F without any concern.
If you have the 3P HVB then it might be a little bit lower where you need to plug in. Not sure about that. I think @macchiaz-o has experienced reduced power modes related to high HVB temps after being parked outside all day. (he lives in the same city as me....) He might have some observations for what temps he gets that "please plug in message" on his display.

 

[SnBGC]

I often worry about this because I've been charging to 100% since I got the car in December. The cold temps here were putting me at around 150 miles at 90% and sometimes I have to go further than that in a day. I needed all the mileage I could squeak out of it. I plan on backing it off as it gets warmer, but I do worry about degradation. Good to see that the battery management appears to be pretty good so far on yours

It could be that charging to 100% on a daily basis really isn't a problem at all (or it is a very very minor issue at best). That is the only choice you get on the Focus Electric so it must not be all that bad for the battery because the usable capacity is about 90% of the actual capacity. And many of those vehicles are still out there with nearly the same usable capacity as when new. I see this on my son's Fiat 500e as well as some other smaller range BEVs out there. As long as they have liquid cooling then they usually last quite a while.

The thing to avoid is charging to 100% (displayed) and then leave it like that for several days. That might not be very good for the battery. If you charge to 100% every day and then use a significant portion of that charge each day then I would bet money that your battery is just fine. ?

 

[BadgerGreg]

Thanks for the analysis. Also, you're really putting on the miles quickly!!

I'm happy to see that we're starting to get real data on degradation (or lack thereof) for vehicles that have legit mileage on them. My MME has just over 20,000 miles and I'm not noticing any degradation yet (although I have yet to fully crunch the numbers). I remember hearing someone representing Ford say that they designed the battery pack to degrade no more than 5% during the first 100,000 miles, assuming normal usage. Your experience seems to show that you're well within that design range.

I'm looking forward to seeing more extensive data as more cars approach 40,000-50,000 miles. More data like this should compel Ford to continue to unlock extra battery capacity. I want my 91 kWh!

 

[SnBGC]

Thanks for the analysis. Also, you're really putting on the miles quickly!!

I'm happy to see that we're starting to get real data on degradation (or lack thereof) for vehicles that have legit mileage on them. My MME has just over 20,000 miles and I'm not noticing any degradation yet (although I have yet to fully crunch the numbers). I remember hearing someone representing Ford say that they designed the battery pack to degrade no more than 5% during the first 100,000 miles, assuming normal usage. Your experience seems to show that you're well within that design range.

I'm looking forward to seeing more extensive data as more cars approach 40,000-50,000 miles. More data like this should compel Ford to continue to unlock extra battery capacity. I want my 91 kWh!

I would be curious to see data from a vehicle with similar miles that DCFCs frequently or exclusively. I wonder if the results would be the same or if more degradation would be observed?

I have yet to see an exact 88 kWh estimated to empty reading but that screen grab I posted is pretty darn close. Perhaps I will see a true 88 kWh around 85F pack temp. If Ford reserved about 11 kWh for the upper and lower limit then I am guessing they might be fairly equal. 5.5 kWh or maybe 6.0 kWh down at the lower end which would be 5.0 to 5.5 at the upper end. In theory, this would mean our actual S.O.C. would be around 95% when the displayed S.O.C. is showing 100%. In the screen grab that I posted, we see actual S.O.C. around 96.3% so perhaps 1.3% of the upper limit is consumed. Eventually the Actual S.O.C. should be equal to the Displayed S.O.C. when all the upper buffer is consumed and at that point we should start to observed some battery degradation. I don't think the degradation is linear but if it were, and you plot out the miles then I should be around 127k miles before any observable degradation occurs.

All this points right back to your statement and validates the engineers are right on target. I might go well past 100k miles before we consume the (estimated) 5% upper limit but a frequent DCFCer might see their buffer consumed sooner than 100k. Sounds reasonable.

I will avoid the extra 91 kWh if allowed. I don't need it. I don't road trip that often but for those that do then the extra usable would be handy. ?

 

[macchiaz-o]

If you have the 4P HVB then you are probably fine with temps up to 100F without any concern.
If you have the 3P HVB then it might be a little bit lower where you need to plug in. Not sure about that. I think @macchiaz-o has experienced reduced power modes related to high HVB temps after being parked outside all day. (he lives in the same city as me....) He might have some observations for what temps he gets that "please plug in message" on his display.

Yes, we're both in the Valley on the Sun [sic]. ?

All I could tell for sure is that I'd get the annoying loss of drive modes, reduction in power, and reduced cabin cooling, on the hottest of days. The car will say something like 125 or 130F or something like that but it's only that hot at close to road level, which is apparently where Ford placed the temperature sensor for the reading we see on SYNC. I didn't write down measurements or anything so this is from memory and might be wrong.

Unlike Greg, I'm unfortunately unable to plug in at work. Also, parking at work is a huge asphalt lot with essentially zero shade opportunities. There are a few trees here and there, but none near where I park. So the car soaks up a lot of heat.

Unless Ford changes something, the Mustang Mach-E does not seem to do anything to cool down its electronics except when the vehicle is running, or if it's plugged in for charge AND within its preferred charge hours.

Sponsored